Solar white light imaging, Herschel Wedge vs. solar film - Forums

Topic starter

Jul 11, 2023

Hi,

For imaging the sun in white light, which one giving better details or contrast, the Wedge or the film [or foil if you call it]?

It will be used with any scope from 40mm up to maybe 200mm aperture.

Ruediger

Jul 11, 2023

Hi Tareq,

I would always prefer the Herschel Wedge. Foil has always some distortion. Also it ages and suffers from small pinholes. In the beginning not dangerous, but disturbing. Foil is the poor men‘s solution for small scopes.

With an aperture beyond 130mm things get anyway a little bit sophisticated. You deal with enormous amounts of energy. At this size you should use glas filters in front of the objective. I used one for my Meade 12“.

using only a wedge at this size means always you have the full energy inside the tube. In case you are only a bit misaligned and the light beam hits the tube itself, or the focuser tube, you will quickly know what melts with a few hundred degree. I had once a Finder scope not properly covered…. After few seconds it was fuming and melted plastic ran out from its back. The cross hair melted completely. All in seconds and only 50mm.

My personal rules: Wedges for scopes up to approx 130mm and no plastic inside and safe focuser, smaller scopes foil, bigger ones glas filters in front of the objective.

this is what I would recommend. Other may have different experiences.

CS
Rüdiger

Helpful Engaging

Tareq Abdulla

Topic starter

Jul 11, 2023

Ruediger:
Hi Tareq,

I would always prefer the Herschel Wedge. Foil has always some distortion. Also it ages and suffers from small pinholes. In the beginning not dangerous, but disturbing. Foil is the poor men‘s solution for small scopes.

With an aperture beyond 130mm things get anyway a little bit sophisticated. You deal with enormous amounts of energy. At this size you should use glas filters in front of the objective. I used one for my Meade 12“.

using only a wedge at this size means always you have the full energy inside the tube. In case you are only a bit misaligned and the light beam hits the tube itself, or the focuser tube, you will quickly know what melts with a few hundred degree. I had once a Finder scope not properly covered…. After few seconds it was fuming and melted plastic ran out from its back. The cross hair melted completely. All in seconds and only 50mm.

My personal rules: Wedges for scopes up to approx 130mm and no plastic inside and safe focuser, smaller scopes foil, bigger ones glas filters in front of the objective.

this is what I would recommend. Other may have different experiences.

CS
Rüdiger

Hi Rüdiger,

Thank you very much for your answer, it is a big help and clear.

I rad that fontal glass filters aren't good quality results compared to foil or Wedge, i agree that foil by the time it may have issues like pinholes, i had one with my small filter foil, even it is not much noticeable but i will never risk using it anyway, and because it is small i will just use the wedge, also i could replace that foil to another foil more suited for imaging than visual.

CS
Tareq

JDJ

Jul 12, 2023

I have used both approaches and agree that the wedge is the way to go. Additionally, I use a solar continuum filter (e.g. https://www.baader-planetarium.com/en/baader-solar-continuum-filter-(540nm).html). The filter combined with the wedge gives great contrast.

Tareq Abdulla

Topic starter

Jul 12, 2023

I have used both approaches and agree that the wedge is the way to go. Additionally, I use a solar continuum filter (e.g. https://www.baader-planetarium.com/en/baader-solar-continuum-filter-(540nm).html). The filter combined with the wedge gives great contrast.

I have Continuum filter, i will use it with any either the wedge or film, just i wanted to know which one is better, so the wedge it is, thank you

Tareq Abdulla

Topic starter

Jul 12, 2023 · Edited: Jul 12, 2023

There is an additional question, i see some using another filter with Continuum, either UV/IR cut or ND filter, are those really necessary? Are they act as ERF for example or just to gave better contrast or what exactly those additional filters do?

Ruediger

Jul 12, 2023

Tareq Abdulla:
There is an additional question, i see some using another filter with Continuum, either UV/IR cut or ND filter, are those really necessary? Are they act as ERF for example or just to gave better contrast or what exactly those additional filters do?

No, they are not. The continuum filter blocks UV/IR. ND can be used.
These questions are answered here: https://www.baader-planetarium.com/de/sonne/weisslicht/7.5nm-solar-continuum-filter-540nm.html

Unfortunately I see it only in German, but they gave exactly the answer on your questions. You may use translation in the browser..

Tareq Abdulla

Topic starter

Jul 13, 2023

Ruediger:
Tareq Abdulla:
There is an additional question, i see some using another filter with Continuum, either UV/IR cut or ND filter, are those really necessary? Are they act as ERF for example or just to gave better contrast or what exactly those additional filters do?

No, they are not. The continuum filter blocks UV/IR. ND can be used.
These questions are answered here: https://www.baader-planetarium.com/de/sonne/weisslicht/7.5nm-solar-continuum-filter-540nm.html

Unfortunately I see it only in German, but they gave exactly the answer on your questions. You may use translation in the browser..

Ok, thank you